Clarify log source

[jakkn]

As a developer using iwa-cli, I have a hard time identifying where these logs are coming from

$ docker compose logs -f
[+] Running 2/2
 ⠿ Network foo-web_default                  Created                                               0.0s
 ⠿ Container foo                            Started                                               0.6s
foo  | Could not find a config file!
foo  | File with injected configuration was generated!

Not until I searched this project for those strings did I understand where the logs came from. An identifier to the logs would be helpful, e.g. a [IWA] prefix:

foo  | [IWA] Could not find a config file!
foo  | [IWA] File with injected configuration was generated!